Former employees and clients of a San Mateo spa that closed last month have told city and state officials that the business shut down without warning — and failed to make good on outstanding wages and gift certificates.

The state Department of Industrial Relations said a former employee of the Sandra Caron European Spa on Third Avenue filed a complaint for $6,000 in unpaid wages for hours worked between July 14 and Oct. 10. If officials find in favor of the plaintiff, the spa may also have to pay nearly $2,800 in penalties, said Erika Monterroza, a spokeswoman for the agency.

A second employee, who worked as an aesthetician and asked that her name not appear in print because she feared reprisal, said the spa owed her more than $300 in wages for the first five days of October. The woman said four massage therapists and another aesthetician also never received their paychecks.

Between seven and 10 former clients of the spa called the San Mateo Chamber of Commerce and the Downtown San Mateo Association about unredeemed gift certificates, association Executive Director Kelly Mitter said.

“They just sort of vanished,” Mitter said. “It’s like somebody went home one night and never came back.”

San Mateo police Lt. Mike Brunicardi said a resident contacted police Wednesday about the spa but didn’t file a report because it was a civil rather than a criminal matter. He added that a gift certificate is a contract between a business and a customer and doesn’t fall under the department’s jurisdiction.

The store had no “closed” sign in the window this week. A for-lease sign and locked door were the only indications the business had closed.

Russell Hitomi, a senior property manager for Coldwell Banker Commercial-Wilbur Properties in Palo Alto, said his company began eviction proceedings after the spa failed to pay its October rent of about $13,000. An unidentified woman then dropped off the keys Oct. 7 or 8, said Hitomi, adding that the business had occupied the building for at least 10 years and signed a five-year renewal lease just two months earlier.

“We’re going to go after them for the entire five years,” Hitomi said. “It may be kind of a moot point, because I’ve heard that (the owner) has filed for bankruptcy.”

Hitomi added that Coldwell Banker plans to bring in a liquidator to buy up the spa’s abandoned equipment and merchandise, which includes massage tables, robes, washers and dryers, facial creams and an assortment of Betty Boop dolls.

On its Web site, the spa bills itself as the “largest day spa in the Bay Area,” housed in an 8,000-square-foot facility. It also advertises a number of job openings, including for a receptionist and massage therapist.

The spa remained operational Friday and appeared to be accepting credit card payments for gift certificates. The spa’s phone was disconnected and owners Lionel and Sandra Caron did not answer a message left at their San Mateo residence or an e-mail seeking comment.

The spa received 1-1/2 stars on the popular Web site Yelp and just three positive reviews out of 29. Complaints mostly center on the decor and customer service, which one user described as “curt and snarly.”

David Finkelstein, an attorney representing the Carons in the dispute with Coldwell, said the two parties were in settlement discussions.

Finkelstein cited the “general downturn in the economy and retail businesses” as the primary reason for the spa’s closure.

It wasn’t clear whether some of the business’ financial difficulties sprang from civil lawsuits filed against it by women who accused an employee of fondling them during massages. A jury convicted 33-year-old masseur Kevin Bradshaw of inappropriately touching two women at Sandra Caron and another San Mateo spa, and he is currently serving a one-year sentence in San Mateo County jail.

In an Oct. 28 document filed in San Mateo County Superior Court, one plaintiff charges that the Sandra Caron spa rehired Bradshaw knowing he had been fired from Massage Envy in San Mateo after being accused of sexually battering a customer.

According to the court filing, Bradshaw regularly engaged in sexual activity with female clients at Sandra Caron and rubbed a customer’s breasts and pubic region without consent just one day before he was accused of making similar advances toward the plaintiff.

Todd Emanuel, the plaintiff’s attorney, said he was representing “multiple victims” in cases involving inappropriate touching at the spa. The spa’s attorney in the case, Peter Dixon, couldn’t be reached for comment.

Customers with Sandra Caron gift cards can apply 25 percent of their certificates’ value to any 60-minute regularly priced spa service at The Spa Studio on South B Street, owner Wendy Narlock said. In addition, former Sandra Caron customers will receive a 30 percent discount at their first appointment.

Narlock said she made the offer because she felt sorry for the customers and wanted to attract new business.

“I hope people don’t think that this is something that happens all the time,” Narlock said. “We’re definitely not a fly-by-night outfit.”

Otto Warmbier was arrested in January 2016 at the end of a brief tourist visit to North Korea. He had been medically evacuated and was being treated at the University of Cincinnati Medical Center when he died at age 22.